Heat exchange device



May 8, 1934. J. J. HOPPES HEAT EXCHANGE DEVICE 2 Sheets-Sheet l OriginalFiled Feb. 14, 1951 III/1111111111111 INVENTOR ATTORNEYS May 8, 1934..1. J. HoPPEs HEAT EXCHANGE DEVICE Original Filed Feb. 14 1931 2Sheets-Sheet 2 INVENTOR ATTORNEYS Patented May 8, i934 @riginalapplication February l-i, 1931, Serial No.

Divided and this application January 25, 1933, Serial No. 653,51

7 Claims.

This invention relates to improvements in that class oi heat exchangedevices in which a heated fluid is passed tfough a fluid-tight casing,the heat oi this fluid being transmitted. to a second fluid passingthrough tubes arranged in the path of the heated iiuid; this applicationbeing a division of my application Serial No. 515,808, led February14th, 1931, upon which issued Letters Patent No. 1,898,727, datedFebruary 21, 1933.

The improved heat exchanger is particularly adapted for use in suchindustries as laundries where large amounts oi heated water unfit forfurther use are available, the heat of which may be transferred to asupply oi clean water of lower temperatures with a consequent increasein operating economy. Since this hot waste water carries a large amountof foreign matter either in suspension or otherwise, the depositingthereof on the tubes lowers the eiiciency of the heat transmission, thedeposit or sludge acting as an insulator.

An object of the invention is to provide a preliminary hopper-shapedsettling chamber wherein a portion of the sludge may be precipitated,thereby preventing such portions from passing into the interior oicasing or" the device.

Another object is the provision oi an improved casing construction sodesigned that the fluid carrying tubes are at all times completelysubmerged, whereby drying and consequent hardening or" the sludge isprevented.

Another object is to provide a casing construction for a heat exchangerior the purpose oi maintaining the temperature the duid receiving theheat at a more const it value. It is obvious that fluctuations in thetemperature oi the heated iiuid is the ca1 or" any fluctuations in thetemperature oi the fluid rec iving the heat. 1n the improved casingconstruction the heating fluid is pe itted to follow the naturaltendency to establish upward currents within itself, the velocity andextent of the movement oi the currents being in direct proportion to theamount ci heat contained therein. Therefore, ii an occasional quantityoi colder waste water passes through the device, the currents will riseto a lesser altitude, as a consequence of which the temperature or thefluids in the upper portions oi the casing is not greatiy reduced.

In the accompanying drawings:

Fig. 1 is a iront elevation of a heat exchanger in which the principlesof the invention are embodied, the view being broken away at points toshow interior elevations.

Fig. 2 is an end elevation of the right hand end of the device, thisview being broken away to show interior constructional details.

Fig. 3 is an enlarged fragmentary longitudinal section on the line 3-3of Fig. 2.

Fig. e is an elevation of the left hand end of the device, the view alsobeing broken away to show portions of the interior details.

Fig. 5 is an enlarged fragmentary vertical section on the line 5 5 ofFig. l, showing details of the tube and header construction.

Fig. 6 is an enlarged fragmentary longitudinal section on the iine 6--5oi Fig. 1i.

Referring to the drawings, the casing of the improved heat-exchanger isessentially a uidtight sheet-metal box, admission and discharge openingsfor the fluid giving up its heat, which will hereafter be termed the hotor waste water, being in the nature oi long, rectangular openings in thelowerniost portions of the end Walls. 1 represents the upper sheet, 2the bottom or oor member, 3 the rear, 4 the front wall and 5 and 23 theend walls. The waste water enters at 6 and ows into a preliminary,hopper-shaped settling chamber '7 adjacent the end wall 5 where aportion of the sludge is deposited. This chamber is formed by an outerwall 8 extending upwardly from the extension 2 of the door sheet 2 to apoint above the level of the upper casing sheet 1.

The settling chamber 7 is closed at its upper end by a horizontal sheet9 secured to the upper edges of the wall 8 and to a Wall member l0 whichin turn is secured to the right-hand edge of the upper sheet 1. Thechamber has a slop ing bottom l1 for the greater portion of its extentfor the purpose oi facilitating the deposit of any sludge, the slopecausing the sludge to gravitate to the bottom '7' of the chamber fromwhere it may be drained oii at intervals through the drain pipe 12.

The flow of hot water is turned downwardly on entering the settlingchamber as shown by the arrows in Fig. 2, then upwardly, there being avertical baiie member 13 longitudinally disposed in the chamber I7;there being a horizontal wall 1B which closes the space in the settlingcham` ber above the inlet on the outer side of the baflie so that allwater must pass beneath the baiiie in proximity to the inclined bottom11. The end wall 5 of the casing forms one side of the charnber andextends upwardly to a point not less in height than the level of theupper casing member 1, and provides an opening 14 between the upper edge5' of the wall member 5 and the chamber top member 9. This opening 14communicates with a vertical channel 15 formed between the end wall 5and a partition member 16 placed in parallel relation therewith andpreferably extending the full width of the casing from front to rear,the front and rear walls oi the channel being extensions of the wallmembers 4 and 3, respectively. The hot water then flows downwardlythrough this narrow vertical channel l5 and into the casing through anopening 17 below the baffle member 16, the bailie 16 extending to withina short distance of the iioor 2 of the casing.

The accompanying drawings show a casing whose interior is divided intotwo compartments by a single vertical, transversely disposed partitionmember 18 in parallel relation with the end walls and joined at itsupper front and rear edges preferably by duid-tight joints to the uppermember and front and rear walls 4 and 3. This partition also extends towithin a short distance of the iieor 2, providing a horizontal opening19 similar to the opening 17. The two compartments mentioned aredesignated C and C', and are termed heat-exchanging chambers, since ineach chamber are inserted interconnected. unitary structures comprisingtubes, headers and other associated details through which the fluid tobe heated is passed. In the present specication the fluid being heatedis termed simply the clean water, while the description of the conduitscarrying the same will appear at a later point.

The path of the ilow of hot water through the chamber C is undulatory,the water arising irnmediately on entering the chamber through theopening 17 by virtue of its heat. As it ascends, heat is lost and thevelocity of this upward current is reduced, and on impinging on theunder surface of the upper sheet 1 the water is diverted to the left,flowing downwardly through the left side of the chamber C along thepartition 18 towards the opening 19. The opening 19 is, of course, theinlet opening to the chamber C', wherein a repetition of the iiow justdescribed occurs. The outlet for the chamber C is also ad jacent theiioor member 2 in the same manner as the openings 17 and 19 are arrangedand is designated as at 20, Fig. 1. The iiow after passing through thisopening 20 is upwardly through a narrow vertical passage 21 formed bythe parallel position of a battle sheet 22 and the end wall 23 at theleft extension of the casing. The passage 21 discharges into anenclosure comprising the walls 24, 25 and 26, Fig. 7, in connection withsuitable front and rear wall extensions forming a fluid-tightpassage-way leading to the discharge connection 27, it being noted thatthe ilow through the enclosure reaches an altitude greater than thelevel of the upper portions of the casing, as the edge 23 of the endwall 23 extends above the upper sheet 1, in the same manner as describedin connection with the upper edge 5. The advantage gained in causing theincoming and outgoing flows of hot water to be at greater elevationsthan the upper portions of the casing is that the casing at all timesremains completely lled with water Whether in operation or not,therefore any sludge that may be deposited within the casing or passagesleading to and from the same, or upon the clean water conduitarrangements, remains in a more plastic condition, being prevented fromdrying and consequent hardening which would result in an expensivecleaning operation. This construction also permits the drainage of thesettling chamber 7 without lowering the level of the water in theinterior of the casing.

By causing the waste water to enter and leave at the lowerrnost portionsof the casing the previously mentioned advantage is gained of allowing ashort-circuiting of any occasional quantities of colder waste water, thepath of such being comparatively direct from the casing inlet 17 to theoutlet 20, the water, by its greater density remaining near the iloor. Afurther minor advantage is that, by the provision of hand-hole openingsnormally covered by cover-plates such as are indicated at 28, Fig. 2,and at 29, Fig. 4, access may be had to the iicor area of the casing forinspection or such cleaning thereof as may be desired. The casing may bedrained by opening a valve (not shown) connected with a drainpipepreferably located near the casing outlet 20.

The improved heat-exchanger is designed to provide that a modiiicationof the effective' counter-iow scheme is employed, the path of the flowof clean water receiving heat starting at the lower left extremity ofthe device and terminating at the lower right portion in proximity tothe waste water inlet. It is clear from the description so far that thepath followed by the waste water is a series of undulations moving fromright to left, and that a chamber such as C encloses a single undulationconsisting of a descending and ascending column of water ofsubstantially rectangular cross-sectional area.

The simplest counter-flow arrangement would be to cause the path ci theclean water to closely conform to the undulatory path of the waste waterin all respects, but I prefer the modied' arrangement such as is shownand described in the present case, wherein the path of the clean waterzig-zags to and fro in a generally upward movement through a descendingcolumn, and conversely to and fro in a generally downward movementthrough an ascending column, of waste water. The exact relation of thepaths one to another may be stated in other words by explaining that across-section taken on a horizontal plane through either an ascending ordescending column of waste water is substantially rectangular in form,the long dimension extending from front to rear, and that the path ofthe clean water within the casing is always parallel to the longdimension.

Such an arrangement has an advantage in that an extended clean waterpath is provided in a relatively small space. There is also an.vadvantage that it is possible that a desired number of tubes andassociated parts may be combined into a unitary structure of which aplurality are employed, each of which may be inserted or withdrawn intoor from the casing independently of the others, all connecting mediumsconveying uids from one to another of the structures be ing made on theoutside of the casing.

The clean water is conveyed throughout the casing interior in tubes 31of which a preferably equal number is associated in each unitarystructure or bank, in the present case there being two banks for eachsingle heat exchanging compartment such as C or C". The tubes arearranged in vertical and horizontal rows, as seen best in Figs. 1 and 5,although it is clear that a staggered arrangement could be employed.Referring to the initial bank, employed in the left portion of thechamber C', the tubes are secured at their forward ends in a flat plate32 and at their farther ends in the raised portion 33' of a hollowheader 33 preferably by a rolling and calking process, this operation attheir connecn. uu

tion with the header 33 being performed through openings in alignmentwith each tube, the openings being closed by the plugs 33C.

The front wall Al of the casing is provided with rectangular openings athrough which the unit is inserted into the casing. Rollers 33d arefitted to the bottom portions of the headers 33 whereby greater ease oiassembly may be secured. The plate 32 is sufficiently large to act as acover for an opening l and through the overlying portions or the plate32 screws are inserted which thread into openings in the front wall 4,and also passing through the overlying flange 34 of a dish-shaped covercasting 34. The dished interior of the cover casting is divided intocompartments by horizontal baies 35 and 36 into the compartments 343,31th and 34C, these baffles being of such height as to bear against theplate 32 and eectually prevent the passage of fluid from any compartmentto another. In the rear header 33 an integral baille 37 is employed,which divides the interior of this header into two compartments 33a and33h. The alignment of the bafiies 35 and 36 in the cover 34 in relationto the baille 37 in the header 33 is such that the compartment 34acommunicates with a plurality of tubes which discharge into thelowermost portion of the compartment 33a, while tubes leading from theupermost portion of the compartment 33a discharge into the lowermostpart of the compartment 34h. The tubes in communication with the upperportion of the compartment 34h lead to the lower portion of thecompartment 33b in the rear header, and from the upper part of thislatter compartment the tubes discharge into the compartment 34C at theupper end portion of the cover 34.

Openings 33 and 39 are provided in the raised portion of the covercasting 34, the opening 38 being an inlet opening where the clean watermakes its initial entrance into the conduit arrangement, communicatingdirectly with the compartment 34a, while the opening 39 communicateswith the compartment 34. It will then be seen that the clean waterflowing into the compartment 34a travels rearwardly through the lowertubes into the compartment 33a and is then returned forwardly to thecompartment 34D, then again in a rearwardly direction into the lowerpart of the compartment 33h, then forwardly into the compartment 34.0and outwardly through the opening 39. Alternate movements are thus madein a direction generally upward, and since the bank as just describedoccupies the left hand portion of the chamber C' in which portion adescending column of waste water is flowing, a heat transfer inaccordance with the preferred modied form of counterflow takes place.

The water issuing from the upper compartment 34C passes through theopening 39 and through a hollow duct 40 into the upper compartment 34Cof the cover 34 or" the succeeding bank of tubes, which bank is placedin the right side of the chamber C. By admitting the fluid to thiscompartment, which is in fact the compartment 34C of the second bank,the water1 flows towards the rearward header and thereafter in agenerally downward direction to the opening 38 in this bank, and is thenconveyed by the duct 41 to the succeeding banks. The generally downwardmovement of the clean water in this bank is also in a directioncounterwise to that of the waste water, which in this half of thechamber is up wardly. The flow of clean water continues as describedthrough all of the plurality of banks of tubes, nally issuing at theoutlet opening 33 in the bank nearest the waste water inlet 1'7.

A plurality of banks such as have just been desc 1ibed are employed inthe heat exchanger. The present drawings show four only, these beingplaced two each in a single compartment such as C or C', therefore thereare two forward and two rearward movements of the clean water for eachascending or descending columns of waste water, or sixteen to and iromovements for two undulations in the heat exchanger illustrated in thedrawings. This provides perhaps the shortest path practical for eitherof the fluids for an exchange of heat of any appreciable economy;certain circumstances may indicate that a more complete abstraction ofthe available heat units in the waste water may be made by providing alonger path for the fluids. The design of the present exchanger lendsitself to such extensions as it is only necessary to employ additionalchambers and banks of clean water conduits, using the casing andconstructions as described, it being understood that a partition 18 isemployed between adjacent chambers.

Having thus described my invention, I claim:

l. In a heat exchange device, a main casing having tubes therein, asettling chamber at one end of said casing having an inclined bottom,said settling chamber being in communication with said casing by apassageway that leads from a point above the bottom of said chamber to apoint at the bottom of said casing, a iiuid inlet leading to saidchamber and a fluid outlet leading from said casing.

2. In a heat exchange device, a main casing, a bank of tubes therein, asettling chamber at one end of said casing having an inclined bottom, afluid inlet in the upper portion of said chamber, a vertically-arrangedbarile adjacent said inlet and extending below the same but terminatingabove said inclined bottom, a communicating passageway between the upperportion of said settling chamber and the lower portion of said casing,and a iiuid outlet leading from said casing.

3. In a heat exchange device, a main casing, a plurality oi tubestherein, a settling chamber at one end of said casing, a pair ofseparated walls forn a passage between the upper end of said settlingchamber and the lower end of said casing for the full width of thecasing and chamber, said settling chamber having an inclined bottom, afluid inlet leading into the upper portion of said settling chamber, abaille wall adjacent said inlet extending the full length of saidsettling chamber and terminating below said fluid inlet, and a wallenclosing the space above said inlet on the outer side or" said baiiiemember.

4. In a heat exchange device, a casing, a plurality of tubes therein,means for supplying liquid to said casing including avertically-extending passage, the entrance to said passage being abovethe desired liquid level to be maintained in said casing and thedischarge end of said passage leading to the extreme lower portion ofsaid casing, and means for discharging liquid from said casing includinga vertical passage-way, the lower end of which communicates with theextreme lower portion of said casing and the upper end of which is abovethe desired uid level to be maintained in said casing.

5. In a heat exchange device, an enclosure, a plurality of tubes in saidenclosure arranged from a point adjacent the bottom to a point adjacentthe top thereof, means for admitting and discharging fluid to saidenclosure at the bottom thereof so arranged as to maintain a constantlevel of fluid in said enclosure about said tubes and permitshort-circuiting of the fluid through said enclosure below said tubes.

6. In a heat exchange device, an enclosure, a plurality of tubestherein, with a space in said enclosure beneath said tubes, a fluidsupply passage leading to the bottom of said enclosure one point atleast of which is above the desired liquid level to be maintained insaid enclosure, and a fluid discharge passage leading from the bottom ofsaid enclosure one point at least of which is above said liquid level,the space in said enclosure beneath said tubes permitting a llow of coldfluid directly therethrough from the supply passage to the dischargepassage.

7. In a heat exchange device, an enclosure, a plurality of tubes thereinwith a space in said enclosure beneath said tubes, a fluid supplypassage leading to the bottom of said enclosure, a lluid dischargepassage leading from the bottom of said enclosure, one point at least ofeach of Said passages being above the desired liquid level to bemaintained in said enclosure, means in said enclosure to direct thewater upwardly and downwardly about said tubes, the space in the bottomof said enclosure permitting ilow of cold fluid directly therethroughfrom the supply passage to the discharge passage.

JOHN J. HOPPES.

